This invention relates to collets for tufting buttons, and is an improvement over the button collet shown and described in U.S. Pat. No. 3,829,935 to Critchfield that was granted Aug. 20, 1974.
The collet shown and described in the foregoing patent comprises a one piece molded plastic body having a peripheral side over which a button shell with assembled button-covering material is adapted to be crimped. The base of the collet has a stem with a hook for receiving a pre-tied tufting loop which is retained by snap locks so as to prevent removal of the tufting loop. During installation of the tufting button onto the upholstered furniture, the button is drawn into the furniture by the tufting loop. During this procedure and depending upon the depth of tuft and manner of installation, the tufting loop can impose extremely high tensile forces onto the hook. Thus, as the tensile force applied by the loop to the hook increases, the hook will open, resulting in substantial distention, and in many instances the hook will be opened up to the point where failure will occur. This failure generally takes place at the junction of the hook and the hook shank, the latter of which is joined to the base of the collet. Of course, the hook could be reinforced at the normal region of failure, but this tends to increase the size of the hook unduly, which is objectionable from the point of view of the manufacturer of upholstered furniture.